Computer Simulation for Analysis of Lattice Polarity of Wurtzite GaN{0001} Film by Coaxial Impact Collision Ion Scattering Spectroscopy

Abstract

We study soliton solutions in scalar field theory with a variety of unbounded potentials. A subset of these potentials have Gaussian lump solutions and their fluctuation spectrum is governed by the harmonic oscillator problem. These lumps are unstable with one tachyonic mode. Soliton solutions in several other classes of potentials are stable and are of kink type. The problem of the stability of these solutions is related to a supersymmetric quantum mechanics problem. The fluctuation spectrum is not equispaced and does not contain any tachyonic mode. The lowest energy mode is the massless Goldstone mode which restores broken translation invariance.

Characterization of Polarity of Plasma-Assisted Molecular Beam Epitaxial GaN{0001} Film Using Coaxial Impact Collision Ion Scattering Spectroscopy

“…On the other hand, the authors have analysed the incident angle dependences of Ga and the N CAICISS signal intensities at 0 • -50 • using computer simulation and have determined that the incident angle dependences of Ga and N signal intensities at 0 • -50 • provide sufficient information for the quantitative analysis of the volume ratio of each domain in the grown film. 6) In this paper, the effects of the initial nitridation of a sapphire(0001) substrate and the thickness of a low-temperature GaN buffer layer on the polarity of grown GaN film have been investigated using CAICISS. The volume ratios of each domain in the grown GaN films were evaluated by making comparisons between the experimental results of the incident angle dependence of Ga and N signal intensities and simulated ones.…”

Dependence of Polarity and Crystal Quality of the HVPE GaN Buffer Layers on the Surface Treatment of Substrates (GaAs and Sapphire)

“…The polarity was characterized by coaxial impact collision ion scattering spectroscopy (CAICISS) [5]. The polarity can be determined from the incident angle where numbers of the reflected He ions becomes maximum, as described in the paper reported by Sonoda et al [6].…”

Characterization of Polarity of Wurtzite GaN Film Grown by Molecular Beam Epitaxy Using NH3

“…We have investigated the polarities of rf plasma-assisted MBE grown GaN films using coaxial impact collision ion scattering spectroscopy (CAICISS) and have analysed the effects of growth conditions [14][15][16][17] and In irradiation effect during growth. 18) In this paper, we report on the polarities of GaN films grown on sapphire(0001) substrates by ammonia-MBE.…”

“…As details of the simulated results are already given in ref. 16, only typical θ -dependences are described below. The Ga curve of the (0001) surface has two separated peaks at θ = 18 • and 42 • .…”